1. Field of the Invention
This invention relates to a latch bolt mechanism, and particularly to a sleeve-type latch bolt mechanism having different latch members arranged in a cylindrical lock-core device and a cylindrical-stem key adapted to ensure effective locking security.
2. Discussion of the Background
Conventionally, most latch bolt mechanisms are constructed with identical latch members, which are combined together and have a keyhole formed therein for being operated by a serrated flat key to effect unlocking or locking operations therewith. This type of known latch bolt mechanism lacks variety and can be easily unlocked by unauthorized persons with flat articles similar to the latch-bolt key. Therefore, locks combined with these conventional latch bolt mechanisms are insecure and can be the cause of considerable property loss.